;(function ($, window) {
    window.IfrMessenger = (function () {
    	
        // 消息前缀, 建议使用自己的项目名, 避免多项目之间的冲突
        var prefix = "eb_messenger",
            supportPostMessage = 'postMessage' in window;

        // Target 类, 消息对象
        function Target(target, name) {
            var errMsg = '';
            if (arguments.length < 2) {
                errMsg = 'target error - target and name are both requied';
            } else if (typeof target != 'object') {
                errMsg = 'target error - target itself must be window object';
            } else if (typeof name != 'string') {
                errMsg = 'target error - target name must be string type';
            }
            if (errMsg) {
                throw new Error(errMsg);
            }
            this.target = target;
            this.name = name;
        }

        // 往 target 发送消息, 出于安全考虑, 发送消息会带上前缀
        if (supportPostMessage) {
            // IE8+ 以及现代浏览器支持
            Target.prototype.send = function (msg) {
                this.target.postMessage(prefix + msg, '*');
            };
        } else {
            // 兼容IE 6/7
            Target.prototype.send = function (msg) {
                var targetFunc = window.navigator[prefix + this.name];
                if (typeof targetFunc == 'function') {
                    targetFunc(prefix + msg, window);
                } else {
                    throw new Error("target callback function is not defined");
                }
            };
        }

        // 信使类
        function IfrMessenger(name) {
            this.targets = {};
            this.name = name;
            this.listenFunc = [];
            this.initListen();
        }

        // 添加一个消息对象
        IfrMessenger.prototype.addTarget = function (target, name) {
            var targetObj = new Target(target, name);
            this.targets[name] = targetObj;
        };

        // 初始化消息监听
        IfrMessenger.prototype.initListen = function () {
            var self = this;
            var generalCallback = function (msg) {
                if (typeof msg == 'object' && msg.data) {
                    msg = msg.data;
                }
                // 剥离消息前缀
                msg = msg.slice(prefix.length);
                for (var i = 0; i < self.listenFunc.length; i++) {
                    self.listenFunc[i](msg);
                }
            };

            if (supportPostMessage) {
                if ('addEventListener' in document) {
                    window.addEventListener('message', generalCallback, false);
                } else if ('attachEvent' in document) {
                    window.attachEvent('onmessage', generalCallback);
                }
            } else {
                // 兼容IE 6/7
                window.navigator[prefix + this.name] = generalCallback;
            }
        };

        // 监听消息
        IfrMessenger.prototype.listen = function (callback) {
            this.listenFunc.push(callback);
        };
        //注销监听
        IfrMessenger.prototype.clear = function () {
            this.listenFunc = [];
        };
        // 广播消息
        IfrMessenger.prototype.send = function (msg) {
            var targets = this.targets,
                target;
            for (target in targets) {
                if (targets.hasOwnProperty(target)) {
                    targets[target].send(msg);
                }
            }
        };
        
        return IfrMessenger;
    })();
})(jQuery, window);
